Influence of burnt clay brick salinity on moisture content evaluated by non-destructive electric methods

This paper presents the results of tests of mass moisture content in saline burnt solid clay brick by the non-destructive dielectric, resistance and microwave methods. Several groups of bricks, kept in respectively aqueous nitrate, chloride and sulphate media varying in their ion content, and in salt-free water (as the reference) were subjected to tests. It is shown that brick salinity considerably influences the indications of the dielectric meter and the resistance meter and this influence is similar for different salt concentrations, resulting in the significant overrating of the evaluated moisture content relative to the real moisture content. It is also shown that brick salinity has little influence on the indications of the microwave meter. The test results were generalized by determining appropriate correlations between mass moisture content U m and indications X of the dielectric, resistance and microwave meters, to be used in building practice.